Fuel Cell Basics

Fuel cells have a very simple structure. The cell itself consists of three layers, one above the other:

The first layer is the anode, the second an electrolyte and the third layer is the cathode.
Anode and cathode serve as catalyst. The layer in the middle consists of a carrier structure which absorbs the electrolyte. In different types of fuel cells different substances are used as electrolyte. Some electrolytes are liquid and some are solid with a membrane structure.

Because one cell generates only low voltage several cells get stacked according to the requested voltage. This arrangement is called "stack".